This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this project is to obtain control data from pregnant rhesus monkeys and to collect blood and fecal samples for analysis. This study will provide a negative control group for a previous study performed at Yerkes that involved challenge of pregnant rhesus macaques with L. monocytogenes during late gestation. In this proposal pregnant monkeys will be given sterilized whipped cream (vehicle) and collected blood and fecal samples at various intervals to ascertain lack of Listeria infection while collecting immune response parameters from blood mononuclear lymphocytes. Both the dam and offspring are returned to the colony after the last blood sample collection.